$port = '/dev/ttyS0';
$ob = Device::SerialPort->new ($port);

$ob->user_msg(1);	# misc. warnings
$ob->error_msg(1);	# hardware and data errors

$ob->baudrate(19200);
$ob->parity("none");
$ob->databits(8);
$ob->stopbits(1);
$ob->handshake('none');
$ob->stty_icrnl(1)     || die "failed setting convert cr to new line";

$ob->read_interval(0) if ($OS_win);
$ob->read_const_time(10000);
#$ob->read_const_time(500);       # 500 milliseconds = 0.5 seconds
 $ob->read_char_time(1);          # avg time between read char
$ob->write_settings || die "no settings";